Jump to content
SAU Community

Recommended Posts

Having voltage issues with my alternator and was looking at maybe doing an upgrade if it was necessary. What sort of amps would be sufficient for my set up. Car is a VL turbo running 2 x 044 pumps (1 is staged to come on at 10psi) , 6 x LS2 coils, 750cc low impedence injectors, Haltech ps2000, no thermo fans, basic stereo with no amps and battery in the boot. Currently have a RB25 alternator in the car which is 80 amps but my be failing higher up in the rpm as you can see in the data log below. Ramped up fine on 17psi but had a smaller drop in voltage, 22psi it broke down under boost.

post-17518-0-23166600-1422347358_thumb.jpg

Link to comment
https://www.sau.com.au/forums/topic/453163-alternator-upgrade/
Share on other sites

you're having the same issue as I am :)

I'm currently running a 85AMP VL Commodore alternator (Bosch replacement) after replacing my 80AMP R33 alternator.. has gotten a touch better, but I'm getting around 12.8volts up top.. and the idle voltage is horrible.

I'm contemplating in getting this one:

http://www.ebay.com.au/itm/Nissan-Skyline-HR33-GTS-RB25DE-120-Amp-3-0L-6-Cyl-Turbo-Non-Turbo-Alternator-/131390382961?pt=AU_Car_Parts_Accessories&hash=item1e977a2371

I would look at upgrading the wire going from the alternator to the battery.

I checked on my RB20, I have 14.1V at idle on the battery but got 15.3V on the alternator.

I investigated a little more and I found that the wire coming from the alternator going to the power connector next to the battry to power all the car is responsible for the total loss in voltage.

So try to check it on your car and upgrade it if you find that is voltage is much higher than the one you see on your battery. Much cheaper and more efficient than getting a more powerful alternator.

  • Like 1

I've added a second 4ga feed and still have issues.

It's because the alterntor itself cannot produce the voltage to suit the car's demand.

I tested the voltage on the alterntor and it's only like 0.2 volts higher than what's being logged on the ECU.

I'm assuming that the Bosch alternator has issues working at high RPM And the factory unit well is just old.

I found cleaning all the earth points in the engine bay made a difference to my S2 33 . Also the voltage regs don't last forever . I got caught out a while back and had to have my OE alternator rebuilt . The reg is the same as those on early Falcon Mitsi alternators - EA EB from memory . I don't think the OE R33 alt is listed in Australian parts catalogs but long time auto sparkys can usually work it out .

My car shows around 14V at the battery and a little higher at the alternator so good enough for me ATM .

I found cleaning all the earth points in the engine bay made a difference to my S2 33 . Also the voltage regs don't last forever . I got caught out a while back and had to have my OE alternator rebuilt . The reg is the same as those on early Falcon Mitsi alternators - EA EB from memory . I don't think the OE R33 alt is listed in Australian parts catalogs but long time auto sparkys can usually work it out .

My car shows around 14V at the battery and a little higher at the alternator so good enough for me ATM .

Adrian, what voltages are you getting with your headlights on & the rear demister?

My alt to battery wiring is brand new as I've just put a new engine harness in the car. Used 16mm welding cable which should be heaps I'd imagine. Is the size of the sense wire critical? I might pull the engine to chassis earth strap off and clean the connections again just to eliminate that.

Also what sort of amps would be sufficient for my set up? Something around the 90 mark would be heaps I'd imagine or am I bettter off upgrading to a 105-110amp unit?

you dont need to upgrade amperage for your requirements. 80 amps is easily sufficient unless the stereo was a killer. it held 14v flat up till about 5k then something happened. looks like either something turned on that pulled excessive power or had a short. the vibration at that rpm is causing something to move(loose connection). the ignition supply to the alternator plug is failing.

does it dip revving up quickly? accelerating quickly or only when speeding up slowly?

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Crazy how good the aero bar looks compared to the stock one
    • Yes, but you will need to rewire all the things that are different. CAS, coils, etc. Yes, but there is no IAT. What? You can use anything you like. It just has to be hooked up so that it will work.     Or are you wanting to just plug and play without having to do any thinking/work?
    • It's been a little over a decade since I bought the S15. As I did on my socials, I'll share some of my favorite pictures from over the years further below. If you haven't realised, pretty much all the pictures in my posts are ones I've taken.  In terms of updates, I don't have pictures, but I acquired a near-perfect pair of fog lights from a friend of mine, so those got swapped in for the pair I already had. As for the JZX110, I just got it back from being fixed. A few weeks back, I was on the highway when I suddenly drove over something with very little time to react. It was probably the size of a soccer ball, but it went under the car and banged into the underside pretty loudly. I pulled over and realized the fluid leaking was fuel, and of course, it was right near my exhaust. This required replacing the fuel tank. If you happen to be in the same predicament, thankfully this car shares a fuel tank with the JZS171, IS200, and IS300, so it wasn't too painful to replace. Enjoy some pictures as mentioned above, including the carnage from the fuel tank and a bonus picture I came across which shows how ridiculously shiny the Bugels are on the 110. So many more pictures I could share of the S15 but this will do for today, enjoy. 
    • Welcome.  Was the mistake the car, or joining us? 😏
    • Yeap, was me and the daughter getting coffee before heading to the new joint to measure up the fridge space and taking some pics that the solar installer wanted of the switch board
×
×
  • Create New...